Hardware PropertiesInterfacing devices
Types of UARTs
Loop Back Plug
DCB sructure detects the management settings for the serial port of the connection device.
DCB structure contains the following members:
DWORD DCBlength - sizeof(DCB)
DWORD BaudRate - baud rate. There is a standard set of : all the rate constants look like CBR_
E.g. CBR_9600, CBR_115200.
DWORD fBinary - Eof character check mode – Windows doesn't support this mode (at least now). Mask $01
DWORD fParity - Parity control Mask $02 – enabling Parity control
DWORD fOutxCtsFlow - Mask $04 – enabling CTS signal control at bytes output.
DWORD fOutxDsrFlow - Mask $08 – enabling DSR signal control at bytes output.
DWORD fDtrControl - Mask $30 – DTR signal control type: values
DWORD fDsrSensitivity - Mask $40 - enabling DSR signal control.
DWORD fTXContinueOnXoff - XOFF continues Tx
DWORD fOutX - Mask $100. Enabling XON XOFF out flow control
DWORD fInX - Mask $200 -//- when receiving
DWORD fErrorChar - Mask $400. Allowing to replace the received byte with a ErrorChar structure member if the reception was erratic (parity mismatch occurred).
DWORD fNull - Mask $800 enable null stripping – skip NULL characters when receiving
DWORD fRtsControl - Mask $3000. Control type:
DWORD fAbortOnError - Mask $4000. Abortion of read/write operations if errors occur
DWORD fDummy2 - Not used
Other structure data
WORD wReserved - Not used
WORD XonLim - min number of bytes in the receiving buffer before the XON character is sent
WORD XoffLim - min number of bytes in the receiving buffer before the XOFFcharacter is sent
BYTE ByteSize - number of bits in a byte is from 4 to 8
BYTE Parity - 0-4=no,odd,even,mark,space parity bit,
BYTE StopBits - 0,1,2 = 1, 1.5, 2 – stop bits, 1,5 used only when 5 bits are sent to 8250 chip.
char XonChar - Tx and Rx XON symbol
char XoffChar - Tx and Rx XOFF symbol
char ErrorChar - Symbol replacing the byte received by mistake
char EofChar - end of input character
char EvtChar - received event character
WORD wReserved1 - Not used
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